JP7448328B2 - Mechanical system that detects missed workpieces - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mechanical system that performs work on a moving workpiece, and more particularly to a mechanical system that detects missed workpieces.

When working on a moving workpiece using a machine such as an industrial robot, the work is performed within the workable area of the machine, so the work may not be completed due to the workpiece speed or amount of workpiece. The workpiece may pass through the workable area. Regarding such mechanical systems, for example, the documents mentioned below are known.

In Patent Document 1, the most upstream robot determines whether each workpiece can be handled, sends data on the workpieces not to be handled to the downstream robot, and the downstream robot determines whether each workpiece can be handled based on the received data. A logistics tracking device has been disclosed that determines the workpiece and sends data on workpieces that are not to be handled to the most downstream robot.

Patent Document 2 discloses a visual sensor that detects the position of a workpiece by acquiring images of a plurality of tracking ranges, an encoder that detects the amount of movement of a conveyor belt, and a system that detects the tracking range that is being passed based on the detected amount of movement. A handling device is disclosed that includes a tracking manager for specifying, a work manager for selecting an article that satisfies a predetermined condition within the specified tracking range, and a control unit for controlling a robot to hold the selected work. There is.

Patent Document 3 discloses that a plurality of articles arranged in a regular arrangement are placed on a tray in a simulation device that simulates an article arrangement operation in a virtual space.

Patent Document 4 describes a robot that transfers a workpiece conveyed by a first conveyor to a mounting plate conveyed by a second conveyor, and a robot that transfers a workpiece conveyed by a first conveyor to a mounting plate conveyed by a second conveyor, and a robot that transfers a workpiece transported by a first conveyor to a mounting plate that is A transfer system is disclosed that includes a robot controller that causes a robot to temporarily place a workpiece acquired from a conveyor in a temporary placement area.

Japanese Patent Application Publication No. 2007-030087 Japanese Patent Application Publication No. 2007-015055 Japanese Patent Application Publication No. 2018-069377 Japanese Patent Application Publication No. 2017-056529

Generally, workpieces that are overlooked by the machine are often treated as defective products. Handling missed workpieces as defective products will reduce yield, so operators may return the workpieces to the upstream process. However, since the operator cannot predict when defective products will occur, it is necessary to continue monitoring the system, which increases the operator's monitoring burden and personnel costs. There is also a quality risk that overlooked workpieces may be mistakenly delivered to final consumers as non-defective products. Furthermore, it is not easy to determine in what state the work was missed.

Therefore, there is a need for technology for detecting missed workpieces in mechanical systems that perform work on moving workpieces.

One aspect of the present disclosure provides a machine that performs work on a workpiece that passes through a workable area, an oversight detection unit that detects a workpiece that has passed a work limit line of the machine without being completed, and a workpiece that has arrived at the workable area. a second sensor that detects the workpiece, a work management unit that manages at least the current position of the workpiece based on at least information of the second sensor, a third sensor that detects the amount of movement of the workpiece; a prediction unit that predicts whether or not the workpiece will pass through the work limit line without completing the work based on information from the management unit and the cycle time of the machine; The arrival time for the workpiece to reach the work limit line is calculated based on the amount and the distance of the workpiece to the work limit line, and based on the arrival time and the cycle time, the time when the workpiece is left unfinished is calculated. To provide a mechanical system that predicts whether or not a work limit line will be passed.

According to one aspect of the present disclosure, a missed workpiece is detected by a machine and information regarding the missed workpiece is notified, so that an operator or another device can take some action on the workpiece at a desired timing. It becomes possible. Notification of missed workpieces reduces the monitoring burden on the operator, and also makes it possible to improve yield and reduce quality risks.

FIG. 1 is a perspective view showing a schematic configuration of a mechanical system in one embodiment. 1 is a block diagram of a mechanical system in one embodiment. FIG. FIG. 3 is a block diagram of a mechanical system in another embodiment. FIG. 7 is a perspective view showing a modification of the mechanical system. 3 is a flowchart showing a schematic operation of the mechanical system.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In each drawing, the same or similar components are given the same or similar symbols. Further, the embodiments described below do not limit the technical scope of the invention or the meaning of terms described in the claims.

FIG. 1 shows a schematic configuration of a mechanical system 1 in this embodiment. The mechanical system 1 includes one or more machines 11 that perform predetermined work on a workpiece 10, a tool 12 attached to an end of the machine 11, and a control device 13 that controls the machine 11 and the tool 12. It is equipped with The workpiece 10 includes an article 10a or a tray 10b on which the article 10a can be placed, and is conveyed by a conveyance unit 14 such as a conveyor or an automated guided vehicle (AGV) to reach a workable area 15 of the machine 11. The machine 11 is a parallel link robot, but may be another industrial robot such as an articulated robot, or may be another industrial machine such as a machine tool or a construction machine. The tool 12 is a suction type hand, and is used, for example, to place four articles 10a on one tray 10b. However, the tool 12 may be a hand with a plurality of claws, or may be another tool, such as a sealing tool, welding tool, screw fastening tool, soldering tool, laser processing tool, etc., depending on the content of work on the workpiece 10. But that's fine. The control device 13 may be a known control device including a processor such as a CPU (central processing unit).

Since the machine 11 performs work on the moving workpiece 10, the workpiece 10 may pass through the workable area 15 without completing the work due to the speed of the workpiece or the amount of workpiece. Therefore, the mechanical system 1 is equipped with a work limit line 16 for each machine 11, or is provided with a work limit line 16 only for the most downstream machine 11 among a plurality of machines 11, and the workpiece 10 is left unfinished. It is configured to detect that the workpiece 10 has been missed when the workpiece 10 passes through the work limit line 16. The work limit line 16 is provided on the downstream side within the workable area 15 in the traveling direction X of the workpiece 10, but may be provided further downstream than the workable area 15 of the machine 11 disposed at the most downstream position (see FIG. (See the rightmost number 16 in 1).

The mechanical system 1 may include a first sensor 17 that monitors the work limit line 16 in order to detect whether the work 10 has been overlooked. The first sensor 17 may be a two-dimensional camera, a three-dimensional camera, or the like that can detect the workpiece 10. The mechanical system 1 may use the first sensor 17 to detect whether the workpiece 10 has passed the work limit line 16 or to detect whether the work on the workpiece 10 has been completed. good. According to the first sensor, it is also possible to detect, for example, whether the article 10a is placed at a predetermined location on the tray 10b, and whether sealing, spot welding, etc. for the predetermined location of the article 10a has been completed.

Alternatively, the mechanical system 1 may include a second sensor 18 that detects the arrival of the workpiece 10. The second sensor 18 may be a two-dimensional camera, a three-dimensional camera, etc. that can detect the position, orientation, amount of movement, etc. of the work 10, but may also be a photoelectric sensor, a contact sensor, etc. that can detect only the position of the work 10. When using the latter sensor, the mechanical system 1 may include, in addition to the second sensor 18, a third sensor 19 capable of detecting the amount of movement of the workpiece 10. The third sensor 19 may be a rotary encoder or the like attached to the rotation shaft of the conveyance section 14. The mechanical system 1 manages at least the current position of the workpiece 10 based on the information of the second sensor 18 and, if necessary, the information of the third sensor 19, and manages at least the current position of the workpiece 10 without using the first sensor 17. Based on the current position of the workpiece 10, it may be detected whether the workpiece 10 has passed the work limit line 16 without completing the work, or it may be detected whether the work on the workpiece 10 has been completed.

Alternatively, when the reference position of the workpiece 10 is known, the mechanical system 1 uses neither the first sensor 17 nor the second sensor 18, but based on the movement amount of the workpiece 10 acquired by the third sensor 19. The current position of the workpiece 10 may be managed, and it may be determined based on at least the current position of the workpiece 10 whether or not the workpiece 10 has passed through the conveyance deceleration line 16b without completing the work, or it may be determined whether or not the workpiece 10 has passed through the conveyance deceleration line 16b without completing the work. It may be determined whether the work on the workpiece 10 existing between the transport acceleration line 16c and the workpiece 10 is completed.

The mechanical system 1 notifies an operator or another device of information regarding the missed work 10 based on the detection of the missed work 10. The missed work notification allows an operator or another device to take some action on the work at a desired timing. Furthermore, the mechanical system 1 may include a work compensation unit 20 that compensates for work based on notification of missed work. The work compensation unit 20 is provided downstream of the work limit line 16, and serves as a dispensing machine for dispensing missed articles 10a or missed trays 10b, a replenishing machine for replenishing missed trays 10b with articles 10a, or missed trays 10b. A conveyor or the like is provided for returning the article 10a or the missed tray 10b to the upstream side of the workable area 15.

FIG. 2 shows the configuration of the mechanical system 1. The control device 13 includes a storage section 22 that stores at least an operation program 21, an operation control section 23 that controls the operation of the machine 11 based on the operation program 21, a mechanical drive section 25 that drives a mechanical drive motor 24, and a tool. A tool drive section 27 that drives a drive motor 26 is provided. The operation program 21 is a program that describes basic operation instructions for the machine 11 according to the work content, and the operation control section 23 issues operation instructions to the machine drive section 25 or tool drive section 27 based on the operation program 21. Send. The mechanical drive section 25 or the tool drive section 27 supplies electricity to the mechanical drive motor 24 or the tool drive motor 26 based on the operation command.

The control device 13 includes a workpiece management unit 28 that manages workpiece information (current position, posture, amount of movement, work status, etc.), and a workpiece management section 28 that manages information on the workpiece (current position, posture, amount of movement, etc.) and converts the information of the workpiece (current position, posture, amount of movement, etc.) from the sensor coordinate system to machine coordinates. The system further includes a converter 29 for converting into a system. The work management unit 28 uses only the second sensor 18, or the second sensor 18 and the third sensor 19, or only the third sensor 19 when the reference position of the work is known in advance. , at least the current position of the workpiece can be managed. Furthermore, when the mechanical system 1 includes a plurality of machines 11, the workpiece management section 28 may manage work distribution of the workpieces to the plurality of machines 11. The work management unit 28 preferably manages work information using a work database as shown in the following table, for example. The work database is synchronized or shared among the plurality of control devices 13.

When the workpiece arrives within the workable area, the workpiece management section 28 continues to send workpiece information (current position, posture, amount of movement, etc.) to the conversion section 29. posture, amount of movement, etc.) from the sensor coordinate system to the machine coordinate system. The motion control section 23 sends a motion command including the target motion of the machine (target position, target speed, target posture, etc.) to the machine drive section 25 according to the information of the workpiece (current position, posture, amount of movement, etc.). continue. As a result, the machine 11 performs work while chasing the workpiece. When the work on a specific work is completed, the work management section 28 continues to send information on the next work (current position, posture, amount of movement, etc.) to the conversion section 29, and the above-mentioned work is repeated. When the workpiece management section 28 manages information on the workpiece (current position, posture, amount of movement, etc.) using a mechanical coordinate system, the conversion section 29 may be provided between various sensors and the workpiece management section 28 .

The control device 13 further includes an oversight detection section 30 that detects an oversight of a work, and a notification section 31 that notifies information regarding the missed work based on information from the oversight detection section 30. The oversight detection unit 30 uses only the first sensor 17 or information from the work management unit 28 to detect whether the work has passed the work limit line without being completed. When using the first sensor 17, the oversight detection unit 30 performs these determinations by applying pattern matching, blobs, etc. to the information from the first sensor 17 to detect a workpiece.

When using the information from the work management section 28, the oversight detection section 30 refers to the aforementioned work database, for example, and determines the article No. 1 current position (X420) is machine No. By comparing with the position of the work limit line (X300) of No. 1, article No. 1 may be detected. Also, the missed detection unit 30 refers to the work database described above, for example, and detects the tray number. 1 current position (X410) is machine No. In addition to comparing the position of the work limit line of No. 1 (X300), By determining the presence or absence of the article in the tray No. 1, the tray No. 1 is placed. 1 may be detected.

The oversight detection unit 30 performs similar oversight detection in embodiments in which other operations such as sealing and welding are performed. For example, the oversight detection unit 30 refers to the above-mentioned workpiece database, compares the current position of the workpiece with the position of the work limit line, and determines whether or not work on the sealing part, welding part, etc. of the workpiece is completed based on the work status. You may judge.

The notification unit 31 notifies the operator or another device of information regarding the missed work. Information regarding the missed work may include the fact that the work was missed, the number of missed works, the unfinished portion of the work, and the like. By notifying the operator of the missed work or the number of missed works, the operator or another device can perform some processing on the missed work at a desired timing. Further, by notifying the unfinished parts of the workpiece, it becomes possible to perform work only on the unfinished parts. Such notification of missed work can reduce the monitoring burden on the operator, and can also promote improvement in yield and reduction in quality risk.

The notification unit 31 notifies another device, for example, the work compensation unit 20, the work management unit 28, etc., of information regarding the missed work. Based on the missed work notification, the work compensation unit 20 takes out the missed items and missed trays, replenishes the missed trays with items, or moves the missed items or trays upstream of the workable area. We will provide compensation for the work, such as returning the work. Further, when a work limit line is provided for each machine, the work management unit 28 may distribute the missed work to the downstream machines 11 based on the missed work notification.

The control device 13 may further include a selection unit 33 that selects a work target from among the plurality of works based on the information from the second sensor. The selection unit 33 may, for example, select good/defective products based on the presence or absence of scratches, or may select whether work is required based on the presence or absence of a label. In this case, the oversight detection unit 30 detects whether or not the selected work object has passed the work limit line without completing the work, and also detects whether the work that has not been selected (for example, a defective product) has simply passed the work limit line. It may also be detected whether or not it has passed.

The control device 13 includes a prediction unit 34 that predicts whether or not the work will pass the work limit line without completing the work based on information from the work management unit 28 and the cycle time of the machine 11, and a prediction unit 34 that predicts whether or not the work will pass the work limit line without completing the work based on the information of the work management unit 28 and the cycle time of the machine 11. The transport controller 35 may also be provided. The prediction unit 34 refers to, for example, the above-mentioned workpiece database, and calculates the movement amount of the workpiece (v=20cm/s) and the article number. Article No. 2 is determined based on the distance to the work limit line of No. 2 (d ₂ =X500-X380). 2 reaches the working limit line (t ₂ = d ₂ /v), and by comparing the arrival time (t ₁ ) with the cycle time (c) (t ₂ -c>0), the product No. 2 will pass the work limit line without completing the work. Furthermore, the prediction unit 34 determines the next article number. A similar prediction is made for 3 (t ₃ -2c>0). Article No. If it is predicted that article No. 3 will pass through the work limit line without completing the work (t ₃ −2c≦0), the conveyance control unit 35 controls article No. The conveyance drive motor 36 is driven at a conveyance speed (v'<d ₃ /2c) such that No. 3 does not pass through the work limit line without completing the work.

FIG. 3 shows the configuration of a mechanical system 1 in another embodiment. In this configuration, the mechanical system 1 includes a host computer device 32, and the host computer device 32 is communicably connected to each control device 13. The host computer device 32 processes information acquired from various sensors such as the first sensor 17, the second sensor 18, and the third sensor 19 at high speed, and transmits various commands to each control device 13 based on the processing results. It is composed of The work management section 28, the conversion section 29, the oversight detection section 30, the notification section 31, the selection section 33, the prediction section 34, and the transport control section 35 are not provided in the control device 13, but are integrated in the host computer device 32. be done. Thereby, various programs and various data can be shared between the plurality of control devices 13, and maintainability of the mechanical system 1 can be improved.

FIG. 4 shows a modification of the mechanical system 1. In this modification, the work compensation section 20 includes a circulation conveyor 37. The circulation conveyor 37 delivers the work 10 if there is no notification that the work 10 has been missed, and returns the missed work 10 to the upstream of the workable area 15 if there is a notification that the work 10 has been missed. This makes it possible for the machine 11 to perform the work again on the missed workpiece 10.

FIG. 5 schematically shows the operation of the mechanical system 1. In step S10, at least the position of the workpiece is detected using the second sensor, and in step S11, the amount of movement of the workpiece is detected using the third sensor. However, if the second sensor can also detect the amount of movement of the workpiece, the current position of the workpiece can be managed only by the second sensor, and the process of step S11 becomes unnecessary. Furthermore, if the reference position of the workpiece is known in advance, the current position of the workpiece can be managed only by the third sensor, so that the process of step S10 is not necessary.

In step S12, at least the current position of the workpiece is managed. When a plurality of machines are provided, work distribution of workpieces to the plurality of machines may be managed. In step S13, at least the current position of the workpiece is converted from the sensor coordinate system to the machine coordinate system. However, when managing workpiece information (current position, orientation, amount of movement, etc.) in a machine coordinate system, the process of step S13 may be performed between step S11 and step S12.

In step S14, the machine is made to follow the workpiece based on the workpiece information (current position, posture, amount of movement, etc.). In step S15, work is performed on the workpiece using a tool. In step S16, it is determined whether the workpiece has passed the work limit line without being completed. If the work passes through the work limit line without being completed (YES in step S16), the missed work is notified to the operator or another device in step S17, and work compensation is performed. If the work has not passed the work limit line without completion (NO in step S16), no notice of missed work is given.

According to the above embodiment, the missed workpiece 10 is detected by the machine 11 and information regarding the missed workpiece 10 is notified, so that the operator or another device can take some action on the workpiece 10 at a desired timing. It becomes possible to apply. Notification of missed workpieces reduces the monitoring burden on the operator, and also makes it possible to improve yield and reduce quality risks.

The above-mentioned "unit" may be configured with a semiconductor integrated circuit, or may be configured with a program executed by a processor. Further, a program for executing the above-described flowchart may be provided by being recorded on a computer-readable non-transitory recording medium, such as a CD-ROM.

Although various embodiments have been described herein, it is recognized that the present invention is not limited to the embodiments described above, but that various modifications can be made within the scope of the following claims. I want to be

1 Mechanical system 10 Work 11 Machine 12 Tool 13 Control device 14 Transport section 15 Workable area 16 Work limit line 17 First sensor 18 Second sensor 19 Third sensor 20 Work compensation section 21 Operation program 22 Storage section 23 Operation control section 24 Mechanical drive motor 25 Mechanical drive section 26 Tool drive motor 27 Tool drive section 28 Work management section 29 Conversion section 30 Missed detection section 31 Notification section 32 Upper computer device 33 Selection section 34 Prediction section 35 Conveyance control section 36 Conveyance drive motor 37 Circulation conveyor

Claims (18)

A machine that performs work on a workpiece that passes through a workable area;
an oversight detection unit that detects the workpiece that has passed through the work limit line of the machine without being completed;
a second sensor that detects the workpiece arriving in the workable area;
a workpiece management unit that manages at least the current position of the workpiece based on at least information from the second sensor;
a third sensor that detects the amount of movement of the workpiece;
a prediction unit that predicts whether or not the work will pass the work limit line without completing the work based on information from the work management unit and the cycle time of the machine;
Equipped with
The prediction unit calculates an arrival time for the workpiece to reach the work limit line based on a movement amount of the workpiece and a distance of the workpiece to the work limit line, and calculates an arrival time for the workpiece to reach the work limit line based on the arrival time and the cycle time. , a mechanical system that predicts whether or not the workpiece will pass through the work limit line without completing the work. The mechanical system according to claim 1, further comprising a notification section that notifies information regarding the missed workpiece based on information from the missed detection section. The apparatus further includes a first sensor that detects the workpiece that has passed the work limit line, and the oversight detection unit determines whether the workpiece has passed the work limit line without completing the work based on information from the first sensor. 2. The mechanical system of claim 1, wherein the mechanical system detects. According to claim 1, when it is predicted that the workpiece will pass through the work limit line without completing the work , the transport control unit controls the workpiece so that it does not pass through the work limit line with the work incomplete. mechanical system. The work management unit further includes a third sensor that detects the amount of movement of the workpiece, and a work management unit that manages at least the current position of the workpiece based on information from the third sensor, and the oversight detection unit is configured to control the workpiece management unit. The mechanical system according to claim 1, wherein the mechanical system detects whether or not the workpiece has passed the work limit line without completing the work based on the information. The mechanical system according to any one of claims 3 to 5, comprising a plurality of the machines, and wherein the work management unit further manages work distribution of the work to the plurality of machines. A plurality of the machines are provided, the work limit line is provided for each machine, and the work management unit distributes the missed work to a downstream machine if the work passes the work limit line without completing the work. The mechanical system according to any one of clauses 3 to 6. The selection unit further includes a selection unit that selects a work target from among the plurality of workpieces based on information from the second sensor, and the oversight detection unit is configured to cause the selected work target to pass through the work limit line without completing the work. The mechanical system according to any one of claims 3 to 7, wherein the mechanical system detects whether or not the selected workpiece has passed a work limit line. a transport control unit that controls transport of the workpiece based on the prediction;
9. A mechanical system according to any one of claims 1 to 8, further comprising: The mechanical system according to any one of claims 1 to 9, comprising a plurality of the machines, and wherein the work limit line is disposed at the most downstream of the plurality of machines and is provided only in the machine. The mechanical system according to any one of claims 1 to 10, wherein the work limit line is provided downstream within the workable area in the traveling direction of the workpiece. According to any one of claims 1 to 11, the information regarding the missed work includes at least one of the fact that the work was missed, the number of missed works, and unfinished parts of the work. mechanical system. The mechanical system according to claim 2 , further comprising a work compensation unit that compensates for the work based on the notification. The machine according to claim 13, wherein the work compensation unit includes a dispensing machine for dispensing the missed work, a replenishing machine for replenishing the work, or a transport machine for returning the missed work upstream of the workable area. system. The mechanical system according to claim 13 or 14, wherein the work compensation section includes a circulating conveyor that returns the missed work to an upstream side of the workable area. The mechanical system according to any one of claims 1 to 15, wherein the machine performs the work while following the workpiece based on the current position of the workpiece. 17. The mechanical system according to claim 1, wherein the workpiece includes an article or a tray on which the article can be placed. 18. A mechanical system according to any one of claims 1 to 17, wherein the machine comprises a robot or an industrial machine.

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